1986 60 met to the Rio Trenen, Saw one flowering bamboo near Lago Trenen. The change going from Chile to Argentina across Paso Trenen (= Paso Manuel Irala) is dramatic. From the ascent up a fertile, well-watered, mild- climate valley, one passes under the "Bicentenario Argentina" arch, to be greeted by a wild wind blowing cinders along, the first cipres, nuevo, acacia, etc. On the Chilean side a man can live on a few hectares; on the Argentinian side it takes hundreds of hectares. The population density reflects this. We set traps in Araucaria/steppe/cinder. Very little vegetation under the araucaria. Out in the steppe was sparse Berberis, Seneb, acacia, nuevo, an ericaceous mat. Saw Rattlebirds drifting around an island of pine, Berberis, chaura. Dec. 13 12 km ESE Paso Trenen (affort), my 19 Sherman, 18 MS, and 2 Steel traps caught 2 also long-juls and 1 alderos sp., seeming to be a fantolium without color or a very small a. olivaceus, Anita's 38 MS and steel traps at the East and 4 cage traps caught 1 mure (later), 1 jun. Aubricomys, and 4 also long-juls. Dec. 15 Seminar at Fundacion Barbado (Gelbfruss, Gervelo Guz, Rene Dibace, grad students Veronica (langa) and Maria (rosa mariguita), + Reprofart. Dec. 16 Sapt 9:15 for John Cadel. Arrived 10 PM, Saw scissor-tailed flycatcher at PCA qps station just north of the Rio Colorado. Saw 15 tamarins (concentrilla)